There has been considerable recent interest in halogen substituted ethanes containing fluorine and hydrogen. Many of these materials can be used not only as blowing agents, solvents and refrigerants, but also as starting materials for preparing other useful compounds. Among the halogen substituted ethanes of note are CF.sub.2 HCF.sub.2 Cl (HCFC-124a) and CHF.sub.2 CHF.sub.2 (HFC-134) which can be prepared by hydrogenolysis of CClF.sub.2 CClF.sub.2 (CFC-114); and CF.sub.3 CH.sub.2 F (HFC-134a) and CF.sub.3 CHClF (HCFC-124), which can be prepared by hydrogenolysis of CF.sub.3 CCl.sub.2 F (CFC-114a). UK Patent Specification 1,578,933, for example, discloses a process for the manufacture of tetrafluoroethane characterized in that certain haloethanes having four or five fluorine atoms (e.g, CClF.sub.2 CClF.sub.2, CCl.sub.2 FCF.sub.3, CClF.sub.2 CF.sub.3, CHClFCF.sub.3, CHF.sub.2 CClF.sub.2 and/or CHF.sub.2 CF.sub.3) are reacted with hydrogen at an elevated temperature in the presence of a hydrogenation catalyst such as palladium supported on charcoal or palladium supported on alumina. As exemplified in UK Patent Specification 1,578,933 hydrogenation of mixtures of 2,2-dichloro-1,1,1,2-tetrafluoroethane and 1,2-dichloro-1,1,2,2 -tetrafluoroethane, produce mixtures of the two isomers of tetrafluoroethane. The formation of CHF.sub.2 CClF.sub.2 /CHClFCF.sub.3 byproducts is exemplified; as is the use of 2-chloro-1,1,1,2-tetrafluoroethane as a starting material to produce CF.sub.3 CH.sub.2 F as the major product.
U.S. Pat. No. 4,766,260 describes an improved gas phase process for the manufacture of 1,1,1,2-tetrafluorochloroethane and 1,1,1-trifluorodichloroethane by contacting a suitable tetrahaloethylene with hydrogen fluoride in the presence of a selected metal on a high fluorine content alumina support. U.S. Pat. No. 4,766,260 discloses that intermediates formed during the course of the reaction can be recycled to the reactor for the production of additional 1,1,1-trifluorodichloroethane and 1,1,1,2-tetrafluorochloroethane; and that 1,1,1-trifluorodichloroethane can be recycled to the reactor for the production of additional 1,1,1,2-tetrafluorochloroethane when this is desired.